From 5edfb53439e7da99a6a382d6507723f99755c7ce Mon Sep 17 00:00:00 2001
From: Anthony Ramine <n.oxyde@gmail.com>
Date: Mon, 2 Apr 2018 00:43:43 +0200
Subject: [PATCH] Properly look for uninhabitedness of variants in
 niche-filling check

---
 src/librustc/ty/layout.rs       | 6 +++---
 src/test/run-pass/type-sizes.rs | 7 +++++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 5f9c305d92f04..16d28ff4266ff 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -1471,10 +1471,10 @@ impl<'a, 'tcx> LayoutCx<'tcx, TyCtxt<'a, 'tcx, 'tcx>> {
 
                     // Find one non-ZST variant.
                     'variants: for (v, fields) in variants.iter().enumerate() {
+                        if fields.iter().any(|f| f.abi == Abi::Uninhabited) {
+                            continue 'variants;
+                        }
                         for f in fields {
-                            if f.abi == Abi::Uninhabited {
-                                continue 'variants;
-                            }
                             if !f.is_zst() {
                                 if dataful_variant.is_none() {
                                     dataful_variant = Some(v);
diff --git a/src/test/run-pass/type-sizes.rs b/src/test/run-pass/type-sizes.rs
index 2f50e63153ea4..0bb18d8729a97 100644
--- a/src/test/run-pass/type-sizes.rs
+++ b/src/test/run-pass/type-sizes.rs
@@ -42,6 +42,12 @@ enum ReorderedEnum {
     B(u8, u16, u8),
 }
 
+enum NicheFilledEnumWithInhabitedVariant {
+    A(&'static ()),
+    B(&'static (), !),
+    C,
+}
+
 pub fn main() {
     assert_eq!(size_of::<u8>(), 1 as usize);
     assert_eq!(size_of::<u32>(), 4 as usize);
@@ -67,4 +73,5 @@ pub fn main() {
     assert_eq!(size_of::<e3>(), 4 as usize);
     assert_eq!(size_of::<ReorderedStruct>(), 4);
     assert_eq!(size_of::<ReorderedEnum>(), 6);
+    assert_eq!(size_of::<NicheFilledEnumWithInhabitedVariant>(), size_of::<&'static ()>());
 }